SECTION 4.0

ENVIRONMENTAL SETTING, IMPACTS, AND MITIGATION

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PROPOSED PROJECT

4.2    Air Quality

This analysis of the potential air quality impacts of the proposed Project was conducted according to CEQA requirements. This section addresses Bay Area Air Quality Management District (BAAQMD) CEQA Guidelines (BAAQMD, 1999) as applied to estimated air pollutant emissions during Project construction and BAAQMD permitting requirements for an Authority to Construct/Permit to Operate (ATC/PTO) application for the operations phase of the proposed Project. U.S. Environmental Protection Agency (EPA) Prevention of Significant Deterioration (PSD) requirements would not apply because this project would not be a major source of air pollutants as defined by the PSD regulations.

This section gives an overview of the local environmental setting as well as the regulatory setting and attainment status of the region. Meteorological data, including temperature and precipitation are discussed, and ambient concentrations for the appropriate criteria pollutants are summarized. Pollutants considered are ozone (O₃); nitrogen oxides (NO_x); carbon monoxide (CO); sulfur dioxide (SO₂); precursor organic compounds (POC), which consist of all carbon-containing organic compounds that can lead to ozone formation, excluding methane, carbon monoxide, and carbon dioxide; particulate matter less than 10 microns (μm) in diameter (PM₁₀); particulate matter less than 2.5 μm in diameter (PM_2.5); and diesel particulate matter, a toxic air contaminant.

4.2.1    Environmental Setting

4.2.1.1    Climatology

The climate of the San Francisco Bay region, along with much of coastal California, is controlled by a semi-permanent high-pressure system that is centered over the northeastern Pacific Ocean. In the summer, the relatively northern location of this strong high-pressure system results in clear skies inland and frequent coastal fog. Very little precipitation occurs during the summer months because storm systems are blocked by the high-pressure system. Beginning in the fall and continuing through the winter, the high-pressure system weakens and moves south, allowing storm systems originating from the Alaska Gulf and the Pacific Ocean into the area. Temperature, winds, and rainfall are more variable during these months.

The predominant regional surface winds during the winter are northerly and southerly. During the spring, summer, and fall, the winds are stronger and westerly. These strong westerly winds are caused by the combination of high pressure offshore and a thermal low pressure resulting from higher temperatures inland.

Atmospheric stability and mixing heights are important parameters in the determination of pollutant dispersion. Atmospheric stability reflects the amount of atmospheric turbulence and mixing. In general, the less stable an atmosphere, the greater the turbulence, resulting in more mixing and better dispersion. The mixing height, measured from the ground upward, is the height of the atmospheric layer in which convection and mechanical turbulence promote mixing. Good ventilation results from a high mixing height and at least moderate wind speeds within the mixing layer. In general, the frequent occurrence of temperature inversions over the San Francisco Bay Area limits this mixing height and consequently limits the availability of air for dilution.

4.2.1.1.1    San Francisco Area Climatology. Because the topography of San Francisco is mostly below 200 feet, the marine layer is able to flow across most of the city, making its climate cool and windy. The speeds of these winds are generally sufficient to carry pollutants away before they can accumulate. Long-term average temperature and precipitation data have been collected in the Mission Dolores area of San Francisco, the surface meteorological station nearest to the Project site, and are presented in Table 4.2-1. Average low and high temperatures (given throughout this section in degrees Fahrenheit [°F]) during the summer vary from the mid-50s to the upper-60s, respectively. Summer precipitation is extremely low due to the strong stationary high-pressure system located off the coast that prevents most weather systems from moving through the area. The Project site receives an average of about 20 inches of rain annually. During the winter, average low and high temperatures vary from the mid-40s to the mid-50s, respectively. More than 80 percent of the precipitation in the area occurs from November through March, generally in association with storm systems that move through the region.

4.2.1.1.2    Pittsburg Area Climatology. In the Carquinez Strait region, low mixing depths and low wind speeds typically occur when the pressure gradient direction shifts to an easterly direction due to a high-pressure system over the Central Valley. Furthermore, if this occurs in the summer or fall, the winds from the Central Valley are warmer, increasing photochemical activity, and contain more pollutants than the usually cooler marine air. An easterly flow is more common during the winter when the high-pressure system over the Pacific Ocean is no longer offshore. During the spring, summer and fall, the air pollution potential in the region is moderated by the strong westerly winds.

Long-term average temperature and precipitation data have been collected at Antioch, the surface meteorological station nearest to the Project site, and are presented in Table 4.2-2. Average low and high temperatures during the summer vary from the mid-50s to the low-90s, respectively. Summer precipitation is extremely low due to the strong stationary high-pressure system located off the coast that prevents most weather systems from moving through the area. The Project site receives an average of 13 inches of rain annually. This amount is lower than most of the region due to a rain-shadow effect caused by Mt. Diablo to the southwest. During the winter, average low and high temperatures vary from the mid-30s to the mid-60s, respectively. About 80 percent of the precipitation in the area occurs from

TABLE 4.2-1
TEMPERATURE AND PRECIPITATION DATA FOR
MISSION DOLORES STATION, SAN FRANCISCO, CALIFORNIA

Source: NCDC, 2005. Location 37.76N 122.43W.
¹       Average temperature and precipitation data represent 1961–1990.

November through March, generally in association with storm systems that move through the region.

4.2.1.2    Existing Air Quality Conditions

The entire Project is within BAAQMD's jurisdiction. However, the majority of the potential impacts to air quality would be on a very local level adjacent to the converter station sites. Existing air quality representative of the two converter station sites is presented below. Existing air quality information is not collected on the Bay. The cable-laying portion of the construction phase of the Project would produce emissions from vessels operating in the Bay only during the estimated 4- to 5-month cable laying period within the overall construction phase. However, due to the short-term, temporary nature of these emissions and the fact that the emissions source would move as the cable-laying progresses, it is not necessary to characterize the existing air quality specifically on the Bay. However, it is not unreasonable to assume that the existing air quality on the Bay is similar to the existing air quality in the air basin. It also makes no difference to the conclusions reached later in this section if slight variations in air quality exist on the Bay.

TABLE 4.2-2
TEMPERATURE AND PRECIPITATION DATA FOR ANTIOCH, CALIFORNIA

Source: NWS, 1999.
¹       Average temperature and precipitation data represent 1961-1990.

4.2.1.2.1    San Francisco HWC Converter Station Site Air Quality. Air quality measurements (for O₃, CO, SO₂, nitrogen dioxide [NO₂], PM₁₀, and PM_2.5) from the BAAQMD-maintained San Francisco, Arkansas Street monitoring station are presented in Tables 4.2-3 through 4.2-4. The Arkansas Street monitoring station is located about 1 mile from the proposed San Francisco HWC Converter Station site and site alternatives. This location was chosen as the primary monitoring site due to its proximity to the Project site. This station was operated in accordance with EPA guidelines for stations collecting data in support of PSD review. For the analysis, the maximum criteria pollutant concentration from the three most recent years of reported air quality data (2001 to 2004) was used. This value is highlighted in bold on Tables 4.2-3 through 4.2-4.

The monitoring data indicate that there were no measured violations of the federal and California Ambient Air Quality Standards (AAQS) for CO, NO₂, SO₂, and PM_2.5 for all averaging periods. Table 4.2-3 shows that the state O₃ AAQS was exceeded in 2004. Table 4.2-4 shows that the state PM₁₀ AAQS was exceeded on several days.

TABLE 4.2-3
AMBIENT CRITERIA POLLUTANT LEVELS AT ARKANSAS STREET STATION,
SAN FRANCISCO, CALIFORNIA (1995–2004 [ppm])

Source: CARB, 2005.
Notes:
Maximum average values occurring during the most recent three years are indicated in bold.
ppm = parts per million.
¹   All 1-hr concentrations are below the California NO₂ ambient air quality standard of 0.25 ppm.
²   All annual average concentrations are below the federal NO₂ ambient air quality standard of 0.053 ppm.
³     The 1-hr concentration for 2004 was above the California O₃ ambient air quality standard of 0.09 ppm but below the federal O₃ ambient air quality standard of 0.12 ppm. All other 1-hr concentrations were below the California O₃ ambient air quality standard and the federal O₃ ambient air quality standard.
⁴   All 8-hr concentrations are below the federal O₃ air quality standard of 0.08 ppm, 8-hour average. Regulatory standard is to maintain 0.08 ppm as a 3-year average of the 4^th-highest daily maximum. Therefore, number of days exceeding standard concentration is not necessarily the number of violations of the standard for the year.
⁵  All 1-hour average concentrations are below the California SO₂ ambient air quality standard of 0.25 ppm.
⁶  All 3-hour average concentrations are below the federal SO₂ ambient air quality standard of 0.5 ppm (1,300 μg/m³).
⁷ All 24-hr concentrations are below the California SO₂ ambient air quality standard of 0.05 ppm (131 μg/m³) and the federal ambient air quality standard of 0.14 ppm (365 μg/m³).
⁸   All annual average concentrations are below the federal SO₂ ambient air quality standard of 0.03 ppm (80 μg/m³).
⁹  All 1-hr concentrations are below the California CO ambient air quality standard of 20 ppm and the federal CO ambient air quality standard of 35 ppm.
¹⁰ All 8-hr concentrations are below the California and federal CO ambient air quality standards of 9.0 ppm.

TABLE 4.2-4
AMBIENT PARTICULATE LEVELS AT ARKANSAS STREET STATION,
SAN FRANCISCO, CALIFORNIA (1995–2004 [μg/m³])

Source: EPA, 2005.
Maximum average values occurring during the most recent three years are indicated in bold.
¹   Measurements are typically collected about every six days. Values reported are estimated number of days that a measurement would have been greater than the level of the standard had measurements been collected every day. The number of days above the standard is not necessarily the number of violations of the standard for the year. All daily average concentrations are below the federal PM₁₀ ambient air quality standard of 150 μg/m³.
²     All annual arithmetic mean concentrations are below the federal PM₁₀ ambient air quality standard of 50 μg/m³.
³     The state PM₁₀ ambient air quality standard was lowered from 30 μg/m³ to 20 μg/m³. State and federal arithmetic means may differ due to being based on different statistical criteria.
⁴     The number of days above the standard is not necessarily the number of violations of the standard for the year. The federal standard is 65 μg/m³ based on the 3-year average of the 98^th percentiles.
⁵     The federal annual PM_2.5 ambient air quality standard is 15 μg/m³ based on the 3-year average. The state annual PM_2.5 ambient air quality standard is 12 μg/m³.
μg/m³ = micrograms per cubic meter.
μm = micrometer.

4.2.1.2.2    Pittsburg Standard Oil Converter Station Site Air Quality. Air quality measurements from Pittsburg, Tenth Street and Concord Treat Boulevard stations are presented in Tables 4.2-5 through 4.2-7. Both stations were operated in accordance with EPA guidelines for stations collecting data in support of PSD review. For the analysis, the maximum criteria pollutant concentration from the three most recent years of reported air quality data (2001-2004) was used. This value is highlighted in bold on Tables 4.2-5 through 4.2-7.

Air quality data for CO, SO₂, NO_x, and O₃ were obtained from data collected at BAAQMD-maintained air monitoring stations located at Tenth Street in Pittsburg and Concord Treat Boulevard. The Concord Treat Boulevard station was used for PM_2.5 because it is the only PM_2.5 monitoring station in Contra Costa County. The Tenth Street location in Pittsburg was chosen as the primary monitoring site due its proximity to the Project site. These data are considered representative of air quality at the Pittsburg Standard Oil Converter Station site.

The monitoring data indicate that the local air quality is in compliance with federal and California AAQS for CO, NO₂, and SO₂ for all averaging periods. Table 4.2-5 shows that the federal one-hour ozone AAQS was not exceeded once in the past 10 years; the more stringent state ozone AAQS was exceeded more frequently (as many as 8 times in one year). The PM₁₀ data in Table 4.2-6 show some exceedances of only the California 24‑hour AAQS. The PM_2.5 data in Table 4.2-7 show some exceedances of the California 24‑hour and annual AAQS.

4.2.2    Regulatory Setting

Federal, state, and local air quality regulations that are potentially applicable to the proposed Project include the following:

• CFR 50, National Ambient Air Quality Standards (federal AAQS)

• Title 17, California Code of Regulations, California Ambient Air Quality Standards (California AAQS)

• BAAQMD Regulation 1, Rule 301, Public Nuisance

• BAAQMD Regulation 2, Rule 1, Authority to Construct, Permit to Operate

• BAAQMD Regulation 2, Rule 2, New Source Review

• BAAQMD Regulation 2, Rule 2, Best Available Control Technology

• BAAQMD Regulation 6, Particulate Matter and Visible Emissions

• BAAQMD Regulation 7, Odorous Substances

• BAAQMD Regulation 8, Organic Compounds

• BAAQMD Regulation 9, Inorganic Gaseous Pollutants

TABLE 4.2-5
AMBIENT CRITERIA POLLUTANT LEVELS AT PITTSBURG,
TENTH STREET (1995 – 2004 [ppm])

Source: CARB, 2005.
Maximum average values occurring during the most recent three years are indicated in bold.
¹   All 1-hr concentrations are below the California NO₂ ambient air quality standard of 0.25 ppm.
²   All annual average concentrations are below the federal NO₂ ambient air quality standard of 0.053 ppm.
ppm = parts per million.
³     Number of days with an 8-Hour average Exceeding Federal Standard Concentration of 0.08 ppm. Regulatory standard is to maintain 0.08 ppm as a 3-year average of the 4^th-highest daily maximum. Therefore, number of days exceeding standard concentration is not the number of violations of the standard for the year.
⁴   All 1-hour average concentrations are below the California SO₂ ambient air quality standard of 0.25 ppm.
⁵   All 3-hour average concentrations are below the federal SO₂ ambient air quality standard of 0.5 ppm (1300 μg/m³).
⁶   All 24-hr concentrations are below the California SO₂ ambient air quality standard of 0.05 ppm (131 μg/m³) and the federal ambient air quality standard of 0.14 ppm (365 μg/m³).
⁷   All annual average concentrations are below the federal SO₂ ambient air quality standard of 0.03 ppm (80 μg/m³).
⁸   All 1-hr concentrations are below the California CO ambient air quality standard of 20 ppm and the federal CO ambient air quality standard of 35 ppm.
⁹   All 8-hr concentrations are below the California and federal CO ambient air quality standards of 9.0 ppm.

TABLE 4.2-6
AMBIENT PARTICULATE LEVELS (<10μm) AT PITTSBURG, TENTH STREET
(1995-2004 [μg/m³])

Source: EPA, 2005.
Maximum average values occurring during the most recent three years are indicated in bold.
¹   Measurements are typically collected about every six days. Values reported are estimated number of days that a measurement would have been greater than the level of the standard had measurements been collected every day. The number of days above the standard is not necessarily the number of violations of the standard for the year. All daily average concentrations are below the federal PM₁₀ ambient air quality standard of 150 μg/m³.
²   All annual arithmetic mean concentrations are below the federal PM₁₀ ambient air quality standard of 50 μg/m³.
³   The state PM₁₀ ambient air quality standard was lowered from 30 μg/m³ to 20 μg/m³ in June 2002. State and federal arithmetic means may differ due to being based on different statistical criteria.
-- = Data not available.
μg/m³ = micrograms per cubic meter.

μm = micrometer.

The EPA established federal AAQS in 40 Code of Federal Regulations (CFR) 50 in response to the federal Clean Air Act (CAA) of 1970. The federal AAQS include both primary and secondary standards for six "criteria" pollutants. These criteria pollutants are O₃, CO, NO₂, SO₂, PM₁₀, and lead (Pb). Primary standards were established to protect human health, and secondary standards were designed to protect property and natural ecosystems from the effects of air pollution.

The 1990 Clean Air Act Amendments (CAAA) established attainment deadlines for all designated areas that were not in attainment with the federal AAQS. In addition to the federal AAQS described above, a new federal PM_2.5 standard and a revised O₃ standard were promulgated in July 1997. Under an interim policy, the PM₁₀ and 1-hour O₃ standards will continue to be implemented for the next several years while the new standards are being phased in. In 1988, as part of the California Clean Air Act, the State of California adopted the California AAQS, which are in some cases more stringent than the federal AAQS. The state and federal AAQS are summarized in Table 4.2-8.

TABLE 4.2-7
AMBIENT PARTICULATE LEVELS (<2.5 μm) AT CONCORD TREAT BLVD. 1995-2004 (μg/m³)

Source: EPA, 2005.
Maximum average values occurring during the most recent three years are indicated in bold.
¹     The number of days above the standard is not necessarily the number of violations of the standard for the year. The federal standard is 65 μg/m³ based on the 3-year average of the 98^th percentiles.
²     The federal annual PM_2.5 ambient air quality standard is 15 μg/m³ based on the 3-year average. The state annual PM_2.5 ambient air quality standard is 12 μg/m³.
-- = Data not available.
μg/m³ = micrograms per cubic meter.

The EPA, the California Air Resources Board (CARB), and the local air pollution control districts determine the air quality attainment status of designated areas by comparing local ambient air quality measurements from the state or local ambient air monitoring stations with the federal and California AAQS. Those areas that meet ambient air quality standards are classified as "attainment" areas; areas that do not meet the standards are classified as "nonattainment" areas. Areas that have insufficient air quality data may be identified as unclassifiable areas. These attainment designations are determined on a pollutant-by-pollutant basis. The San Francisco Bay Area has been designated as a federal nonattainment area for O₃ and as a state nonattainment area for O₃ and PM₁₀. The attainment status for all other criteria pollutants is considered attainment. Table 4.2-9 presents the attainment status (both federal and state) for the San Francisco Bay Area.

As mentioned above, both the EPA and CARB are involved with air quality management in the San Francisco Bay Area along with BAAQMD. The area of responsibility for each of these agencies is described below.

The EPA has ultimate responsibility for ensuring, pursuant to the CAAA, that all areas of the United States meet, or are making progress toward meeting, the federal AAQS. The state of California falls under the jurisdiction of EPA Region IX, which is headquartered in San Francisco. EPA requires that all states submit State Implementation Plans (SIPs) for

TABLE 4.2-8
RELEVANT FEDERAL AND CALIFORNIA AMBIENT
AIR QUALITY STANDARDS

¹   Title 17, California Code of Regulations, California AAQS for ozone (as volatile organic compounds), carbon monoxide, sulfur dioxide (1‑hour), nitrogen dioxide, and particulate matter (PM₁₀), are values that are not to be exceeded. The visibility standard is not to be equaled or exceeded.
²   40 CFR 50. National AAQS, other than those for ozone and based on annual averages, are not to be exceeded more than once a year. The 80-hr ozone standard is based on a three-year average of the fourth-highest daily maximum.
³   Concentrations are expressed first in units in which they were promulgated. Equivalent units are given in parentheses and based on a reference temperature of 25°C and a reference pressure of 760 mm of mercury. All measurements of air quality area to be corrected to a reference temperature of 25°C and a reference pressure of 760 mm of mercury (1,013.2 millibar); ppm in this table refers to ppm by volume, or micromoles of pollutant per mole of gas.
⁴   New federal 8-hour ozone and fine particulate matter (PM_2.5) standards were promulgated by EPA on July 18, 1997. The federal 1-hour ozone standard was revoked by EPA on June 15, 2005.
⁵   Nitrogen dioxide (NO₂) is the compound regulated as a criteria pollutant; however, emissions are usually based on the sum of all oxides of nitrogen (NO_x).
⁶   California Air Resources Board established new standards for PM₁₀ and PM_2.5 in June 2002.
⁷   Annual federal standard is 3-year average. The 24-hour federal standard is 3-year average of 98^th percentile.
⁸   In sufficient amount to reduce the prevailing visibility to less than 10 miles when the relative humidity is less than 70%. "Prevailing visibility" is defined as the greatest visibility which is attained or surpassed around at least half of the horizon circle, but not necessarily in continuous sectors.
AAQS = Ambient Air Quality Standard
mg/m³ = milligrams per cubic meter
μg/m³ = micrograms per cubic meter
ppm = parts per million

TABLE 4.2-9
FEDERAL AND STATE ATTAINMENT STATUS FOR THE BAY AREA

Source: CARB 2006

nonattainment areas that describe how the federal AAQS will be achieved and maintained. The EPA has delegated this attainment responsibility to CARB.

CARB, in turn, has delegated attainment responsibility to regional or local air quality management districts (or air districts), such as the BAAQMD. CARB is responsible for attainment of the California AAQS, implementation of nearly all phases of California's motor vehicle emissions program, and oversight of the operations and programs of the regional air districts.

Each air district is responsible for establishing and implementing rules and control measures to achieve air quality attainment within its district boundaries. The air district also prepares an air quality management plan (AQMP) that includes an inventory of all emission sources within the district (both man-made and natural), a projection of future emissions growth, an evaluation of current air quality trends, and any rules or control measures needed to attain the AAQS. This AQMP is submitted to CARB, which then compiles AQMPs from all air districts within the state into the SIP. The responsibility of the air districts is to maintain an effective permitting system for existing, new, and modified stationary sources, to monitor local air quality trends, and to adopt and enforce such rules and regulations as may be necessary to achieve the AAQS.

The applicable regulations related to the potential air quality impacts from the proposed Project are primarily administered (either independently or cooperatively) by the BAAQMD. The BAAQMD has been delegated responsibility for implementing the federal, state and local regulations on air quality in the nine-county region that includes the proposed Project area. The proposed Project is subject to BAAQMD regulations that apply to new sources of emissions, to the prohibitory regulations that specify emissions standards, and to the requirements for evaluation of air pollutant impacts for both criteria and toxic air pollutants. The following sections include the evaluation of the Project's compliance with the applicable BAAQMD requirements. The BAAQMD will review the proposed Project in conjunction with its permit review process. Impacts caused by the Project to the attainment status of any applicable ambient air quality standard will be generally assessed by the BAAQMD. However, no new exceedances of any applicable air quality standard would be expected due to Project operation.

4.2.3    Environmental Impacts

This section describes the analyses conducted to assess the potential air quality impacts from the proposed Project. Emissions estimates for both construction and operation of the proposed Project are presented. Separate activities within the construction phase were addressed separately due to their occurrence at different periods within the overall 27- to 30-month construction phase.

4.2.3.1    Thresholds of Significance

Air quality impacts would be considered potentially significant if the following were to occur:

• Project construction activities would not be in compliance with feasible air pollution control measures set forth in BAAQMD CEQA Guidelines (BAAQMD, 1999).

• Project emissions would be higher than applicable, established significant emission levels or, when compared to background emission levels, emissions would represent a significant increase in emissions (CEQA Checklist and BAAQMD CEQA Guidelines).

• Operations would not comply with BAAQMD rules and regulations and, therefore, could not pass pre-construction review and receive a permit (BAAQMD Rules and Regulations).

• Activities would expose sensitive receptors to substantial pollutant concentrations (CEQA Checklist and BAAQMD Rules and Regulations).

Other potential significant impact criteria (CEQA Guidelines, Appendix G) were considered but rejected from this analysis because they are not applicable to this Project. These include:

• Conflict with or obstruct implementation of the applicable air quality plan. The BAAQMD has air quality plans in place for ozone and particulate matter; both of these pollutants are addressed in terms of the significance criteria listed above.

• Violate any air quality standard or contribute substantially to an existing or projected air quality violation. Pollutant emission levels would be too low for this to occur.

• Result in cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under applicable federal or state ambient air quality standard. This Project would not contribute considerable long-term cumulative pollutant emissions.

• Create objectionable odors affecting a substantial number of people. The Project would not emit objectionable odors.

4.2.3.2    San Francisco HWC Converter Station

4.2.3.2.1    Construction-related Impacts. The primary emission sources during construction include: fugitive dust from disturbed areas due to demolition/site remediation, grading, excavating, and construction at the site; heavy equipment exhaust emissions; commuter vehicle and delivery truck traffic exhaust emissions. Impacts for these categories are identified in the sections below.

Fugitive Dust. A particulate matter emission factor of 1.3 lb/hr of PM₁₀ per acre was used to estimate fugitive dust emissions (MRI, 1996). The construction plans estimate that 5.6 acres would be disturbed during construction at the San Francisco HWC Converter Station site.

Based on the construction schedule, the worst-case monthly emissions would occur at some point during 12 months of demolition and site preparation, and construction. This would result in uncontrolled emissions of approximately 60 to 80 pounds of PM₁₀ per day. Assuming 50 percent control efficiency from frequent water applications on active construction surfaces during hours of construction (or other equivalent dust suppression measures), these emissions would be reduced to approximately 30 to 40 pounds per day. The estimated controlled worst-case construction dust emissions is identified as Impact AIR-1 (refer to Table 1 of Air Quality Appendix D for additional information).

Installation of onshore transmission cables for both AC and DC would also be required during the construction phase. The majority of these cables would be installed by digging a trench, placing the cables and then backfilling the trench. Fugitive dust would be generated during these activities. One major difference between the onshore cable construction and converter station site construction is that onshore cable installation progresses from point to point rather than continuing to occur at the same location. This difference would tend to shorten the duration of air pollutant emissions at any given location along the cable route. Other differences are that a smaller area would be disturbed and fewer pieces of equipment would be used. Therefore, air quality impacts from cable installation would be less than from the converter station construction. However, Impact AIR-1 would apply to the onshore cable installation activity as well. Once construction of the onshore cable line was complete, there would no longer be impacts to air quality.

Impact AIR-1: Fugitive Dust Emissions. The Project proposes to use fugitive dust suppression with water and other methods to control construction-related emissions. The use of chemical additives is not planned. Controlled worst-case fugitive dust is estimated to be 29 pounds per day; 0.32 tons per month; and 2.6 tons over the 27- to 30-month construction period for the San Francisco site. Without fugitive dust control measures the impact is considered potentially significant.

Mitigation Measure AIR-1: Fugitive Dust Controls. Best achievable control measures (BACM) shall be utilized during construction phases of the Project. Fugitive dust control measures are stipulated by BAAQMD Regulation 6 (BAAQMD, 1999) and shall include all of the following as applicable to the Project site:

• Water all active construction areas at least twice daily

• Cover all trucks hauling soil, sand, and other loose materials or require all trucks to maintain at least two feet of freeboard

• Pave, apply water three times daily, or apply (non-toxic) soil stabilizers on all unpaved access roads, parking areas and staging areas at construction sites

• Sweep daily (with water sweepers) all paved access roads, parking areas, and staging areas at construction sites

• Sweep streets daily (with water sweepers) if visible soil material is carried onto adjacent public streets

• Hydroseed or apply (non-toxic) soil stabilizers to inactive construction areas (previously graded areas inactive for 10 days or more)

• Enclose, cover, water twice daily or apply (non-toxic) soil binders to exposed stockpiles (dirt, sand, etc.)

• Limit traffic speeds on unpaved roads to 15 mph

• Install sandbags or other erosion control measures to prevent silt runoff to public roadways

• Replant vegetation in disturbed areas as quickly as possible

Implementation Responsibility:  Project proponent/construction contractor

Requirements and Timing:         Implement fugitive dust control measures on an ongoing basis during all site preparation and construction activity

Monitoring Requirements:          City of Pittsburg to monitor and ensure compliance

Resulting Level of Significance. Implementation of Mitigation Measure AIR-1 would reduce or limit Impact AIR-1 to a less-than-significant level.

This analysis of PM₁₀ as fugitive dust treats dust only as a criteria air pollutant and not as a carrier of any potentially hazardous material. All remediation activities conducted on this Project shall be performed in strict compliance with site-specific health and safety plans. Compliance with the health and safety plans will ensure protection of both worker safety and health and the general public health.

Equipment Exhaust Emissions. Equipment exhaust would be a second source of emissions during construction. Equipment-specific emissions factors were used to estimate emissions for all criteria pollutants from construction equipment (SCAQMD, 2005). Table A.4-3 in Appendix A presents a list of equipment to be used during construction and the estimated number of pieces of equipment that would operate during each month of construction for the San Francisco site and the Pittsburg site, respectively. The San Francisco site would use more construction equipment than the Pittsburg site. Emissions from equipment would occur over a 27- to 30-month period.

Further, the kinds of construction equipment commonly used are primarily diesel-powered and emit diesel particulate matter. The California Air Resources Board (CARB) has identified diesel engine particulate matter as a toxic air contaminant (TAC) and known carcinogen.

The worst-case hourly, daily, monthly, and annual emissions for the San Francisco HWC Converter Station site are presented in Table 4.2-10. Construction emission calculations are provided in Table 2 in Appendix D. Worst-case monthly emissions are based on an assumption that each piece of equipment would operate 176 hours per month during each month of scheduled activity. Worst-case hourly emissions were estimated by dividing worst-

TABLE 4.2-10
ESTIMATED CRITERIA POLLUTANT EMISSIONS FROM CONSTRUCTION EQUIPMENT EXHAUST FOR SAN FRANCICO HWC CONVERTER STATION

¹     Worst-case hourly emissions were estimated by dividing worst case monthly emissions by 176 hours.
²     Using the estimated construction schedule and the utilization factor for each piece of equipment, monthly emissions were estimated for each piece of equipment assuming 176 hours of use per month. Worst case month is month 13.
³     Worst case annual emissions were estimated by summing emissions for each 12-month period (i.e., months 1-12, 2-13, etc.) during the 27- to 30-month construction period and taking the maximum emissions for the worst 12-month period (i.e., months 7-18).

case monthly emissions by 176. Worst-case daily emissions were estimated assuming an eight-hour workday. Annual emissions were estimated by summing the monthly emissions for all equipment and determining the 12-month period having the highest emissions (months 7 through 18); emissions for this 12-month period were summed to get the annual emissions.

Impact AIR-2: Equipment Exhaust Emissions. See Table 4.2-10 for emissions estimates for the San Francisco HWC Converter Station site. The impact of these emissions would be considered to be potentially significant.

Mitigation Measure AIR-2: Exhaust Controls. The following controls pertaining to equipment emissions (BAAQMD, 1999) shall be implemented during construction to reduce emissions from construction equipment exhaust:

• Use alternative fueled construction equipment, as practical

• Minimize idling time

• Maintain properly tuned equipment

• Limit the hours of operation of heavy duty equipment and/or the amount of equipment in use

Implementation Responsibility: Project proponent/construction contractor

Requirements and Timing:         Implement exhaust control measures during all applicable construction activities

Monitoring Requirements:          City of Pittsburg to monitor and ensure compliance

Resulting Level of Significance. Implementation of Mitigation Measure AIR-2 would reduce or limit Impact AIR-2 to a less-than-significant level.

Equipment exhaust would also be generated during installation of the onshore cables (AC and DC). However, as stated above, the transmission line construction progresses from point to point rather than continuing to occur at the same location. This difference would tend to shorten the duration of air pollutant emissions at any given location along the cable route. Other differences are that a smaller area would be disturbed and fewer pieces of equipment would be used. Therefore, air quality impacts from onshore cable installation would be less than from the converter station site construction. However, Impact AIR-2 would apply to the onshore cable installation activity as well. Once construction of the onshore cables was complete, there would no longer be impacts to air quality.

On-road Construction Traffic Exhaust Emissions. Another source of emissions during converter construction is exhaust from construction worker commute vehicles and from delivery vehicle trips to the San Francisco HWC Converter Station site. The estimated number of construction workers is shown in Table A.4-2, and peaks at 45 workers between months 12 and 19. These workers are expected to be drawn from the existing labor pool in the area and are not expected to have long commute distances. Therefore, a maximum of 45 local vehicle round trips per workday would result. Due to this relatively small number of commuters compared to existing traffic in the area and the temporary nature of the construction period, the air quality impact from construction worker commute traffic would be negligible and less than significant.

The estimated number of construction delivery trucks coming to the San Francisco HWC Converter Station site is shown in Table A.4-4. Delivery truck trips would peak at fewer than 500 trips per month or about 22 trips per average workday based on 22 workdays per month. The delivery truck trip length would vary but about 30 percent of the deliveries (up to 700 deliveries of electrical equipment over a 6-month period per site), are expected to originate from the Port of Oakland. The round trip distance between the Port of Oakland and the San Francisco HWC Converter Station site is about 30 miles. If this distance represents the average delivery truck trip length, total delivery trip lengths of about 690 truck-miles per day would be expected for the average workday. A typical tractor-trailer emits about 0.035 pounds per mile of NO_x and lesser amounts of the other criteria pollutants (Emfac Emission Model 2002 Version). Total estimated truck traffic emissions of NO_x would be about 24 pounds per day for the San Francisco deliveries. Daily emissions of the other criteria pollutants would be less. Due to the small amount of emissions compared to existing emissions in the area and the temporary nature of the construction period, the air quality impact from construction delivery truck traffic would be negligible and less than significant.

4.2.3.2.2    Operations-related Impacts. The Project does not include generation of electrical power; therefore, emissions of the air pollutants typically associated with power generation would not occur during Project operation. Operational emissions from the San Francisco HWC Converter Station site would be exclusively from required intermittent testing of one diesel-fueled emergency generator and two diesel-fueled emergency fire pumps. The San Francisco HWC Converter Station would have one 900-kilowatt diesel engine generator set to provide emergency electrical power during power outages and two 225 kW diesel engines each powering one firewater pump. Operation of the emergency diesel engines is only expected to occur for routine testing/maintenance purposes. This should be no more than a few hours per month at each site. Estimates of pollutant emissions from the diesel engines are shown in Table 4.2-11. Each of these diesel engines shall be required to obtain an ATC/PTO from the BAAQMD.

TABLE 4.2-11
OPERATIONAL EMISSION ESTIMATES FOR
EMERGENCY DIESEL ENGINES¹ AT EACH CONVERTER STATION

¹   Emissions factors are EPA Tier 2 non-road diesel compliance requirements. Actual engines installed may emit less.
     Each converter station would have one diesel generator and two diesel fire pumps for a total of 1,350 kW.
     Emissions estimated for testing only. Annual usage estimated at 50 hours.

The emissions values provided in Table 4.2-11 would be considered negligible with respect to air quality impacts from operation at both the San Francisco and Pittsburg Converter Station sites. As such, the CEQA significance determination is less than significant. Per Regulation 2, Rule 1, Sections 301 and 302, "Authority to Construct and Permit to Operate" (Amended 06/15/05), the Project proponent shall submit an application to the BAAQMD to obtain an Authority to Construct and Permit to Operate for the emergency diesel engines at each converter station. The diesel engines shall be required to comply with all applicable BAAQMD regulations including Regulation 2, Rule 5, New Source Review of Toxic Air Contaminants. All diesel engines will be CARB certified in compliance with BAAQMD requirements. Demonstration of no significant human health impacts shall be required prior to issuance of the ATC/PTO.

Operation of the proposed Project would increase the efficiency of power transmission in the Bay Area. The Project would create a new, shorter transmission path into the northern San Francisco peninsula. DC transmission line losses are less than a typical AC transmission line, and the Project would relieve congestion in the transmission grid. Accordingly, it is estimated that 20 MW (or 175,200 MW hours, energy saved in a given year) (CAISO, 2005) of power that is currently lost without the Project would be saved when the Project was operating. An estimate of the air pollution emissions that would be reduced by generating 20 MW less electrical power is shown in Table 4.2-12. These estimates are based on the emissions from a state-of-the-art combined cycle gas turbine power plant using the best available air pollution control technology. Daily emissions assume 24 hours per day of operation and monthly emissions assume 30 days per month of operation. These emission reductions are included for comparison purposes only; no direct reduction of air pollutant emissions associated with power generation is proposed as part of the Project. As such, an impact with a CEQA significance determination was not developed.

TABLE 4.2-12
ESTIMATED CRITERIA POLLUTANT EMISSIONS REDUCTIONS
FROM ANTICIPATED 20 MW IN POWER SAVINGS

Notes:
¹   From new state-of-the-art combined cycle gas turbine power plant equipped with best available air pollution control technology. Plant size of 500+ MW. Emissions scaled linearly to 20 MW.
²     Based on 720 hours per month.
³     Based on 12 months per year.

4.2.3.3    Pittsburg Standard Oil Converter Station

4.2.3.3.1    Construction-related Impacts. As described in Section 4.2.3.2.1, the primary emission sources during converter station construction include: fugitive dust; heavy equipment exhaust emissions; commuter vehicle and delivery truck traffic exhaust emissions. Impacts for these categories are identified in the sections below.

Fugitive Dust. A particulate matter emission factor of 1.3 lb/hr of PM₁₀ per acre was used to estimate fugitive dust emissions (MRI, 1996). The construction plan calls for the 7.5 acres to be disturbed during construction at the Pittsburg Standard Oil Converter Station site, including the proposed access road. The estimated controlled worst-case construction dust emissions are identified as Impact AIR-1 (refer to Section 4.2.3.2.1 and Table 1 of Air Quality Appendix D for additional information).

As described in Section 4.2.3.2.1, installation of onshore transmission cables for both AC and DC would also be required during construction phases. On the basis of that discussion, Impact AIR-1 would be applicable to construction of the onshore transmission cables.

Impact AIR-1: Fugitive Dust Emissions. The fugitive dust emissions impact (Impact
AIR-1) described in Section 4.2.3.2.1 applies to the Pittsburg Standard Oil Converter Station site. The Project proposes to use fugitive dust suppression with water and other methods to control construction-related emissions. The use of chemical additives is not planned. Controlled worst-case fugitive dust is estimated to be 39 pounds per day; 0.43 tons per month; and 3.4 tons over the 27- to 30-month construction period for the Pittsburg site. Without fugitive dust control measures the impact is considered to be potentially significant.

Mitigation Measure AIR-1: Fugitive Dust Controls. Mitigation Measure AIR-1 described in Section 4.2.3.2.1 shall be applied at the Pittsburg Standard Oil Converter Station site.

Implementation Responsibility:  Project proponent/construction contractor

Requirements and Timing:         Implement fugitive dust control measures on an ongoing basis during all site preparation and construction activity

Monitoring Requirements:          City of Pittsburg to monitor and ensure compliance

Resulting Level of Significance. Implementation of Mitigation Measure AIR-1 would reduce or limit Impact AIR-1 to a less-than-significant level.

This analysis of PM₁₀ as fugitive dust treats dust only as a criteria air pollutant and not as a carrier of any potentially hazardous material. All remediation activities conducted on this Project shall be performed in strict compliance with site-specific health and safety plans. Compliance with the health and safety plans would ensure protection of both worker safety and health and the general public health.

Equipment Exhaust Emissions. Equipment exhaust would be a second source of emissions. Equipment-specific emissions factors were used to estimate emissions for all criteria pollutants from construction equipment (SCAQMD, 2005). Table A.4-3 in Appendix A presents a list of equipment to be used during construction and the estimated number of pieces of equipment that would operate during each month of construction for the Pittsburg site. Emissions from equipment would occur over a 27- to 30-month construction period.

Further, the kinds of construction equipment commonly used are primarily diesel-powered that emit diesel particulate matter. The California Air Resources Board (CARB) has identified diesel engine particulate matter as a toxic air contaminant (TAC) and known carcinogen.

The worst-case hourly, daily, monthly, and annual emissions for the Pittsburg Standard Oil Converter Station site are presented in Table 4.2-13. Construction emission calculations are provided in Table 2 in Appendix D. Worst-case monthly emissions are based on an assumption that each piece of equipment would operate 176 hours per month during each month of scheduled activity. Worst-case hourly emissions were estimated by dividing worst-case monthly emissions by 176. Worst-case daily emissions were estimated assuming an 8-hour workday. Annual emissions were estimated by summing the monthly emissions for all equipment and determining the 12-month period having the highest emissions; emissions for this 12-month period (i.e., months 7 through 18) were summed to get the annual emissions.

TABLE 4.2-13
ESTIMATED CRITERIA POLLUTANT EMISSIONS FROM CONSTRUCTION EQUIPMENT EXHAUST FOR PITTSBURG STANDARD OIL
CONVERTER STATION

¹     Worst-case hourly emissions were estimated by dividing worst case monthly emissions by 176 hours.
²     Using the estimated construction schedule and the utilization factor for each piece of equipment, monthly emissions were estimated for each piece of equipment assuming 176 hours of use per month. Worst case month is month 8.
³     Worst case annual emissions were estimated by summing emissions for each 12-month period (i.e., months 1-12, 2-13, etc.) during the 27-month construction period and taking the maximum emissions for the worst 12-month period (i.e., months 7-18).

Impact AIR-2: Equipment Exhaust Emissions. The equipment exhaust emissions impact (Impact AIR-2) described in Section 4.2.3.2.1 applies to the Pittsburg Standard Oil Converter Station site. See Table 4.2-13 for emissions estimates for this site. Without mitigation measures this impact is considered to be potentially significant.

Mitigation Measure AIR-2: Exhaust Controls. Mitigation Measure AIR-2 described in Section 4.2.3.2.1 shall be applied to the Pittsburg Standard Oil Converter Station site.

Implementation Responsibility:  Construction contractor

Requirements and Timing:         Implement exhaust control measures during all applicable construction activities

Monitoring Requirements:          City of Pittsburg to monitor and ensure compliance

Resulting Level of Significance. Implementation of Mitigation Measure AIR-2 would reduce or limit Impact AIR-2 to a less-than-significant level.

Equipment exhaust would also be generated during construction of the onshore DC and AC transmission cable. Impact AIR-2 would apply to the onshore cable installation activity as well.

On-road Construction Traffic Exhaust Emissions. Another source of emissions during converter construction is exhaust from construction worker commute vehicles and from delivery vehicle trips to the Pittsburg Standard Oil Converter Station site. The estimated number of construction workers is shown in Table A.4-2, and peaks at 45 workers between months 12 and 19. These workers are expected to be drawn from the existing labor pool in the area and are not expected to have long commute distances. Therefore, a maximum of 45 local vehicle round trips per workday would result. Due to this relatively small number of commuters compared to existing traffic in the area and the temporary nature of the construction period, the air quality impact from construction worker commute traffic would be negligible.

The estimated number of construction delivery trucks coming to the Pittsburg Standard Oil Converter Station site is shown in Table A.4-4. Delivery truck trips are estimated at fewer than 400 trips per month or about 17 trips per average workday based on 22 workdays per month. The delivery truck trip length would vary but about 30 percent of the deliveries (up to 700 deliveries of electrical equipment over a 6-month period per site), are expected to originate from the Port of Oakland. The round trip distance between the Port of Oakland and the Pittsburg site is about 66 miles. If this distance represents the average delivery truck trip length per site, total delivery trip lengths of about 1,518 truck-miles per day would be expected for the average workday. A typical tractor-trailer emits about 0.035 pounds per mile of NO_x and lesser amounts of the other criteria pollutants (EMFAC Emission Model 2002 Version). Total estimated truck traffic emissions of NO_x would be about 53 pounds per day for the Pittsburg deliveries. Daily emissions of the other criteria pollutants would be less. Due to the small amount of emissions compared to existing emissions in the area and the temporary nature of the construction period, the air quality impact from construction delivery truck traffic would be negligible and less than significant.

4.2.3.3.2    Operations-related Impacts. The Project does not include generation of electrical power; therefore, emissions of the air pollutants typically associated with power generation would not occur during Project operation. Operational emissions from the Pittsburg Standard Oil Converter Station site would be exclusively from required periodic testing of one diesel-fueled emergency generator and two diesel-fueled emergency fire pumps as described in Section 4.3.2.2.2.

The emissions values provided in Table 4.2-11 would be considered negligible with respect to air quality impacts from operation at the Pittsburg Standard Oil Converter Station site. As such, the CEQA significance determination is less than significant.

4.2.3.4    Offshore DC Cable Route

4.2.3.4.1    Construction-related Impacts. Installing the offshore cable would involve marine operations that produce exhaust emissions. The cable ship (C/S) Giulio Verne, cable barges and dredges would produce emissions during construction. The dynamic positioned (DP) C/S Giulio Verne has five main diesel engine-generators (one acting as a redundant spare) that produce electrical power to drive the propulsion, DP and other operating systems. For the proposed Project, only four engines would be in service. Each engine is rated at 2,268 brake horsepower (bhp) and has electromechanical controls, turbochargers, aftercoolers, and original standard injectors and injection pumps for controlling NO_x emissions. The fuel consumption control due to these devices has a reductive influence on NO_x emissions.

As mitigation, the Project proponent intends to use low sulfur diesel fuel oil in the Giulio Verne while it is operating in the San Francisco Bay to reduce emissions of SO₂. Equipment-specific emissions factors were used to estimate emissions for all criteria pollutants from marine vessels (EPA, 1991). Marine Operations Construction emission calculations are provided in Table 3 in Appendix D. Once construction of the approximately 56-mile-long submarine HVDC cable line was complete, there would no longer be impacts to air quality.

Criteria Pollutant Impacts. The total construction emissions from each of the different Project marine construction activities are on an order of magnitude of about 1,375 pounds (equal to about 0.7 ton) per day, with NO_x being the largest quantity (see Table 4.2-14). The BAAQMD has not established CEQA impact significance criteria applicable to construction activities using marine vessels. Therefore, the corollary significance criterion of whether the emissions would pose a significant increase in existing emissions was evaluated.

Multiple cable-laying scenarios are under consideration at this time. One scenario would involve first laying cable from Suisun Bay to Pittsburg utilizing a barge, and then laying cable from Suisun Bay to San Francisco utilizing the C/S Giulio Verne. This scenario includes the possible use of up to 3 splices of the cable. The second scenario would involve laying cable from Suisun Bay to Pittsburg and San Francisco simultaneously using the barge and the C/S Giulio Verne, respectively. This scenario would not require splicing of the cable. The following discussion is based on the first scenario because it would result in higher total emissions. The simultaneous use of the barge and the C/S Giulio Verne would result in higher daily emissions (e.g., a two-thirds increase), but lower total emissions (e.g., up to a 15 percent decrease) and less time on the Bay (e.g., up to 30 fewer days).

TABLE 4.2-14
TYPICAL MARINE EQUIPMENT EMISSIONS DURING CONSTRUCTION

Notes:
Mass emissions are calculated by the following equation: Em = EF x hrs x Equipment # x P.
Em = Mass of emissions (lbs).
EF = Emission Factor for each type of engine operated (lbs/hr); Provided in top half of this table.
hrs = Work hours per month (hours per month * utilization factor * capacity factor).
Hours per month equal 720 for Cable Ship and Cable Barge and equal 176 for Dredge.
Capacity Factor is engine average power output divided by engine rated output for a typical day.
Engine # = The number of engines on the particular vessel.
P = Power per Engine (horsepower).

Because of the non-attainment status of the region, the BAAQMD is required to develop an Air Quality Plan to address the actions it anticipates to achieve attainment for the region. The Air Quality Plan addresses emissions of POC and NO₂ (as precursor pollutants to ozone) and Particulate Matter. The BAAQMD has published projected POC, NO₂ and PM₁₀ emissions (BAAQMD, 2000) within the San Francisco Bay air basin. Their estimates of the district-wide emissions of these pollutants for planning year 2006 are shown in Table 4.2-15. The projected emissions are on an order of magnitude of hundreds of tons per day.

TABLE 4.2-15
BAAQMD PROJECTED DISTRICT-WIDE CRITERIA
POLLUTANT EMISSIONS FOR 2006

Source: BAAQMD 2000, Table 1. CO and SO₂ emissions not included by BAAQMD because they are attainment pollutants
Notes:
CO = carbon monoxide.
NO_x = nitrogen oxides.
PM₁₀ = particulate matter less than 10 microns in diameter.
POC = precursor organic compound.
SO₂ = sulfur dioxide.
¹   PM₁₀ emissions include 103 tons per day from "other sources" which include entrained road dust, construction operations and wind blown dust.

While the NO_x emissions from the Giulio Verne may appear to be large, the BAAQMD has no published significance criteria for short-term, mobile marine vessel emissions. However, this EIR assumes that the BAAQMD may consider the Project emissions of NO_x to be potentially significant without mitigation. They would be unavoidable and temporary and would end when the ship concludes operation in the Bay. The NO_x emissions increase of 0.15 percent would likely be too small to be discernable to the results of ozone modeling. The NO_x emissions increase would also be too small and too distant from any ambient air monitoring station to cause an exceedance of the NO₂ ambient air quality standard.

A comparison of the projected district-wide emission rates to the peak construction emission rates for the Project and the percentage increase in emissions due to the Project is presented in Table 4.2-16. For each of the activities comprising the construction phase, the increase would be 0.15 percent or less of the projected background emissions. On the basis of this discussion, the following Impact AIR-3 is identified.

Impact AIR-3: Marine Construction Impact – Criteria Pollutants. Based on Project marine emissions rates in comparison to background levels, the air quality impacts of criteria

TABLE 4.2-16
COMPARISON OF BAAQMD PROJECTED DISTRICT-WIDE CRITERIA POLLUTANT EMISSIONS FOR 2006 TO ESTIMATED PROJECT MARINE CONSTRUCTION EMISSIONS

¹     PM₁₀ emissions include 103 tons per day from "other sources" which include entrained road dust, construction operations and wind blown dust.
Notes:
NO_x = nitrogen oxides.
PM₁₀ = particulate matter less than 10 microns in diameter.
POC = precursor organic compound.

pollutant emissions of the marine construction phase are considered to be potentially significant.

Mitigation Measure AIR-3: Marine Vessel Emission Controls. The following shall be implemented to control emissions from vessels owned by Prysmian:

• Use California diesel, Purinox, biodiesel, or other fuel (whichever is feasible and would result in lowest emissions)

• Minimize diesel engine fuel usage as much as possible

• Use shore-side power when docked instead of running engines, where feasible

Resulting Level of Significance. Implementation of Mitigation Measure AIR-3 would reduce or limit Impact AIR-3 to a less-than-significant level.

Implementation Responsibility:  Project proponent/construction contractor

Requirements and Timing:         Implement approved marine vessel emission controls during all marine vessel operations in San Francisco Bay

Monitoring Requirements:          City of Pittsburg to monitor and ensure compliance

Diesel Particulate Impacts. It is highly unlikely that the diesel PM from the Giulio Verne would result in a significant increase in health risk to any exposed population. The emissions from the vessel would be on the Bay, removed from sensitive receptor populations and persist for only a few months. The vessel would move along the cable installation route and not remain in one location for extended periods of time. The health effects of diesel PM are associated with long term, chronic exposure and are generally assessed using a 70-year lifetime cancer exposure. Those exposure scenarios are inconsistent with the nature of the potential exposure to emissions from the construction phase of this Project. On the basis of this discussion, the following air quality impact is identified:

Impact AIR-4: Marine Construction Impact – Toxic Air Contaminants. Although there are no established impact significance criteria set forth by BAAQMD, the diesel PM emissions from marine construction may be potentially significant.

Mitigation Measure AIR-4: Implement Mitigation Measure AIR-3.

Resulting Level of Significance. Implementation of Mitigation Measure AIR-4 would reduce or limit Impact AIR-4 to a less-than-significant level.

Implementation Responsibility:  Project proponent/construction contractor

Requirements and Timing:         Implement approved marine vessel emission controls during all marine vessel operations in San Francisco Bay

Monitoring Requirements:          City of Pittsburg to monitor and ensure compliance

4.2.3.4.2    Operations-related Impacts. No air quality impacts are associated with the operation of the offshore cable.

4.2.4    References

BAAQMD (Bay Area Air Quality Management District). 1999. BAAQMD CEQA Guidelines Assessing the Air Quality Impacts of Projects and Plans. December.

     2000. Bay Area 2000 Clean Air Plan and Triennial Assessment, BAAQMD, Adopted December 20.

     2001. Revised San Francisco Bay Area Ozone Attainment Plan for the 1-Hour National Ozone Standard, BAAQMD, Adopted October 24.

CAISO (California Independent System Operator). 2005. Initial Economic Ranking of Alternatives – Results to Date. July 7.

CARB (California Air Resources Board). 2005. CARB ADAM website (http://www.arb.ca.gov/adam/welcome.html). Accessed November 2.

     2006. CARB website at http://www.arb.ca.gov/desig/adm/adm.htm, accessed on Feb. 13.

EPA (U.S. Environmental Protection Agency). 1985. Compilation of Air Pollution Emission Factors. AP-42. September.

     1991. 40 CFR 94, 94.8 Table A-2 Voluntary Emission Standards.

     2005. EPA AirData website (http://www.epa.gov/air/data/reports.html). Accessed November 2.

MRI (Midwest Research Institute). 1996. Improvement of Specific Emission Factors (BACM Project No. 1). March 29.

NWS (National Weather Source). 1999. Historical Weather Summary (1961-1990).

SCAQMD (South Coast Air Quality Management District). 2005. Off-road Mobile Source Emission Factors posted at SCAQMD website (http://www.aqmd.gov/ceqa/handbook/
offroad/offroad.html). Accessed November 7.